Sewing machine feed-dog mechanism



April 6, 1937. F BRI G 2,075,973

SEWING MACHINE FEED-DOG MECHANISM Filed July 23, 1956 2 Sheets-Sheet 1 l I INVENTOR HOWLAND E BRIGGS 2 Shets-Sheet 2 H. F. BRIGGS SEWING MACHINE FEED-DOG MECHANISM Filed July 23, 1936 R5 2 N m T T M A w 2AM L w H mm R vw 8 April 6, 1937.

Patented Apr. 6, 1937 2,075,973 V SEWING MACHINE FEED-DOG MECHANISM Howland F. Briggs, Buffalo, N. .Y., assignor to Consolidated Packaging Machinery Corporation, Buflalo, N. Y., a corporation of New York Application July 23, 1936, Serial No. 92,119

10 Claims.

This invention relates to a feed-dog operating mechanism for a sewing machine and comprises means for providing accurate and. speedy adjustment of the stroke of the feed-dog whereby the number of stitches per inch may be varied. The present feed-dog mechanism is designed to be more rigid than existing types of feed-dog mechanism in order that heavier types of textiles may be fed with the same accuracy and rapidity as the existing types feed lighter textiles. A particular field of utility for which the feed-dog mechanism is designed is in the closing of filled or unfilled textile bags made of heavy, fine-mesh cloths, such as are now being used for the packaging of certain commodities. Heretofore most burlap and other textiles used for making bags have been of very coarse, loose weave, but with the advent of modern packaging certain commodities are being enclosed in bags capable of preventing the escape of all but the finest dust. In order that closures may be applied to these bags the sewing machines for applying the closures must be capable of applying evenly-spaced stitches having the proper tension applied to each stitch. Existing types of feed-dog mechanisms were found to be incapable of so operating on many materials, hence the present invention is designed to provide mechanism sturdy enough to accomplish the purpose and which is instantaneously adjustable from one stitch length to another in order that the most economical stitch may be applied.

The present invention is an improvement upon the feed-arm mechanism disclosed and claimed in the United States Letters Patent to George I-Ioepner, No. 1,263,767, patented April 23, 1918.

The present invention is particularly designed to be used in a sewing machine provided with certain improvements disclosed and claimed in certain United States Letters Patent and applications therefor as follows: The thread take-up for the needle thread is disclosed and claimed 1n Letters Patent No. 2,025,754 to Paul Kuhlig, patented December 31, 1935. The looper and looper operating mechanism is disclosed and claimed in application Serial No. 757,080 to Howland F. Briggs and Robert N. Cundall, filed December 12,

Reference is made to the foregoing patents and application only for the purpose of notifying the public that details herein disclosed are not to be considered disclaimed, it being obvious that 55 machines.

The objects and advantages of the present device will be more readily apparent from the following specification.

Referring to the drawings wherein like numerals refer to like parts throughout:

Fig. 1 is a side elevation of a sewing machine having the present invention incorporated therein and having most of its front cover or wall removed for the purpose of clarity;

Fig. 2 is a vertical section taken on line 2-42 of Fig. 1, certain parts of Fig. 1 being eliminated for the purpose of clarity, and the rear wall of the sewing machine being cut away to the rear of the plane of the view for the purpose of showing certain parts of the present invention;

Fig. 3 is a side elevation partly in cross-section, taken on line 3-3 of Fig. '2, showing the opposite side of the present invention from that shown in Fig. 1;

Fig. 4 is a horizontal cross-section taken on line l4 of Fig. 2, looking in the direction of the arrows; and.

Fig, 5 is a partial side elevation of the outer surface of the rear wall of the sewing machine.

Referring to Fig. 1 there is disclosed a sewing machine enclosed in a housing comprising a rear wall 15 and end and top walls formed by an integral flange IS. A partial front wall I! completes the fixed housing which is preferably provided with a cover (not shown) in such a manner that the same can be readily removed. A horizontal shaft I8, mounted in bearings l9 and 20 formed upon the rear wall of the housing, is driven by a pulley 2! connected by a belt (not shown) to some suitable source of power. An eccentric 22 at the end of the shaft operates a pitman 23 connected to a bell crank 24 which is connected to and reciprocates the needle bar 25 and needle 26. A thread take-up cam 21 mounted adjacent the end of the needle bar operates upon the needle thread in the manner disclosed and claimed in the aforementioned Letters Patent No. 2,025,754 to Paul Kuhlig, dated December 31, 1935. An eccentric at the opposite end of the housing operates a pitman 3| which motivates looper mechanism '32 to operate a looper 33 in the manner disclosed and claimed in the aforementioned application of Howland F. Briggs and Robert N. Cundall,Serial No. 757,080, filed Dccember 12, 1934. The frame is formed with a throat opening 35 through which a portion of the material being sewed, such as the mouth of a bag, can pass while guided between a presser foot 36 and a throat plate 31. The throat plate 31 is provided with an opening 38 through which the feed-dog 39 operates, and. is also provided with a second opening 40 through which the needle 26 operates.

The feed-dog operating mechanism comprises a lever 45, at the lower end of which the feeddog 39 is affixed, which is formed so as to have spaced arms 46 and 41 the upper ends of which embrace a sliding block 48 cooperating with the feed-dog actuating cam 49 mounted upon shaft l8. The sliding block 48 is slidably guided vertically and horizontally in a. guide member 5| fixed to the top and rear walls of the frame, and between collars 52 and 53 fixed to the shaft l8. Block 48 is permitted to slide vertically between the arms 46 and 41, which are braced by a cross bar 54 to form a rigid structure, but is horizontally restrained so that the lever 45 rocks horizontally about a pivot (to be described) in accordance with the horizontal throw of eccentric 49. The upper end of block 48 is provided with a. diagonal slot 55 within which is guided a roller pin 56 exwnding between the arms of the lever. As the block slides vertically the diagonal slot rocks lever 45 backward and forward about the pivot, which therefore must be a universal joint connecting the lever to the frame imparting orbital feeding movement to the feed-dog asdescribed and claimed in the aforementioned-patent to George Hoepner.

The improvement of the present invention comprises a universal joint comprising two axes at right angles, one of which is readily adjustable to provide varying ratios between the upper and lower portions of lever 45 whereby the length of the feeding stroke is changed. This mechanism comprises a joint holding member 60 mounted upon a bolt 6| extending through a slot 62 in the wall Hi. The head 63 of the bolt is of greater diameter than the width of the slot. The holder 66 is provided with a tongue 64 fitting into the slot 62 and vertically slidable therein. Shoulders '65 defining the tongue 64 engage shoulders 66 at the sides of the groove 62. Tightening of nut 61 on bolt 6| rigidly locks the holder 65 to the frame in adjusted position. Holder 66 is provided with a depending portion 18 located centrally of arms 45 and 47 and carrying a pivot 1| provided with a flanged head 72 and extending at right angles to the bolt 6| into the space between arms 46 and 41. The pivot H extends through a collet 15 pivotally mounted on pins 16 and H fixed to arms 46 and 41, respectively. Pivot II is threaded at its forward extremity and carries a nut 18 and washers i9 and 88 engaging the sides of the collet F5. The pivot H is formed with reduced portions defining shoulders against which washers 19 and 80 may bear to limit the tightening of nut 18 whereby the collet 15 may be locked vertically but is permitted to oscillate about pivot II in accordance with the lateral throw of eccentric 49, thereby translating the lateral movementof eccentric 49 into lateral movement of the feed-dog 39. Pins 16 and 1! permit lever 45 to rock with respect to the joint holder 66 and collet 15 in accordance with the movement imparted thereto by slot 55, thereby imparting transverse movement to the feed-dog 39 and causing the same to pass into and out of engagement with the material being sewn. Since the two movements of the feed-dog occur simultaneously an orbital movement results which imparts intermittent movement to the material between each stitch forming stroke of the needle 26.

The head 63 of bolt 6| is preferably provided with an indicator 80 and the outer surface of wall i5 is preferably provided with a series of graduations 8| whereby the operator can instantly determine at what height to place the joint holder 66 in order to form the desired stitch. Adjustment is accomplished by loosening nuts 18 and 61 and sliding the joint holder 60 to its desired position as indicated bythepointer 89. Nuts 78 and 61 are thereupon tightened and the machine will thereafter form the desired number of stitches per inch as indicated by the symbol opposite the graduation 8|.

In Figs. 1 and 2 there is shown a thumb screw 90 and check nut 9| at the upper end of arm 46. The inner end of screw 90 is preferably reduced or tapered to fit a hole in the side of block 48. Before loosening the universal pivot the shaft l8 should be turned by hand until the screw 90 can be made to enter the hole in block 48. This looks the lever 45 in a fixed position during adjustment of the pivot; otherwise the lever would drop until roller 55 reached the bottom of slot 55, thereby necessitating delicate realignment of the feed-dog after each adjustment. The checknut 9| locks the screw 90 against turning accidentally during operation of the machine.

The preferred form of the invention has herein been described and explained, but it should be readily apparent to those skilled in the art that modifications in detail and arrangement are permissible. Such modifications as come within the scope of the following claims are considered a part of my invention.

I claim:

1. In a sewing machine, a frame, a feed-dog for imparting feeding movement to the material being sewn, a feed-dog lever carrying said feeddog and cooperating means for imparting orbital movement to a part of said feed-dog lever, a pivot longitudinally fixed with respect to said lever about which said lever oscillates in one direction, a collet carried by said pivot and retained against movement in said direction of oscillation, a pivot holder and a second pivot carried thereby and extending through said collet, said pivot being adjustably fixed to said collet and permitting oscillation thereof in the direction normal to the first direction of oscillation, and means for adjustably connecting said pivot holder to the frame longitudinally of said lever.

2. In a sewing machine, a feed-dog operating in an orbital movement intermittently to advance material being stitched by said machine, a forked lever carrying said feed-dog at one end and provided at its opposite end with means to engage driving mechanism for causing a part of said lever to traverse an orbital path, a frame supporting the foregoing mechanism, a pivot holder mounted on said frame at one side of said lever and means for adjusting said holder longitudinally with respect to said lever, a pivot fixed to said holder and extending into the space between the arms of said lever, a collet rotatably mounted on said pivot between the arms of said lever, said pivot being provided lever about said pivots being at right angles to the axis of rotation of said collet about said first pivot.

3. In a sewing machine, a feed-dog, a lever carrying said feed-dog, and means for imparting orbital movement to a part of said lever, a universal pivot connected to said lever and permitting translation of said orbital movement to the feed-dog whereby to impart feeding movements to the material, and means .to adjust a part of said universal pivot longitudinally of said lever whereby to vary the length of said feeding movements.

4. In a sewing machine, a feed-dog, a lever carrying said feed-dog, and means for imparting orbital movement to a part of said lever, a universal pivot connected to said lever and permitting translation of said orbital movement to the feed-dog whereby to impart feeding movements to the material, and means to adjust a part of said universal pivot longitudinally of said lever whereby to vary the length of said feeding movements, said universal pivot comprising a collet pivotally attached to said lever and a pivot adjustably and pivotally attached to said collet.

5. In a sewing machine, a feed-dog having an orbital movement, a feed-dog lever carrying said feed-dog and an eccentric imparting fixed, orbital movement to a part of said lever, a frame carrying the foregoing mechanism, a universal pivot connecting said lever to said frame, said pivot comprising two axes of oscillation at right angles to each other, and means whereby one of said axes may be adjusted longitudinally of said lever.

6. In a sewing machine, a frame, a feed-dog for imparting feeding movement to the material being sewn, a feed-dog lever carrying said feed-dog and cooperating means for imparting orbital movement to a part of said feed-dog lever, a pivot longitudinally fixed with respect to said lever about which said lever oscillates in one direction, a collet carried by said pivot and retained against movement in said direction of oscillation, a pivot holder and a second pivot carried thereby and extending through said collet, said pivot being adjustably fixed to said collet and permitting oscillation thereof in the direction normal to the first direction of oscillation, means for adjustably connecting said pivot holder to the frame longitudinally of said lever, and means to lock said lever in fixed position during adjustment of said pivot holder.

7. In a sewing machine, a feed-dog operating in an orbital movement intermittently to advance material being stitched by said machine, a forked lever carrying said feed-dog at one end and provided at its opposite end with means to engage driving mechanism for causing a part of said lever to traverse an orbital path, a frame supporting the foregoing mechanism, a pivot holder mounted on said frame at one side of said lever and means for adjusting said holder lon gitudinally with respect to said lever, a pivot fixed to said holder and extending into the space between the arms of said lever, a collet rotatably mounted on said pivot between the arms of said lever, said pivot being provided with means to clamp said pivot holder in adjusted position longitudinally of said collet while permitting rotation thereof, pivots rotatably connecting said collet to the arms of said lever whereby said lever may rotate with respect to said collet in the direction normal to the first mentioned direction, the axis of rotation of said lever about said pivots being at right angles to the axis of rotation of said collet about said first pivot, and means to lock said lever in fixed position during adjustment of said pivot holder.

8. In a sewing machine, a feed-dog, a lever carrying said feed-dog, and means for imparting orbital movement to a part of said lever, a universal pivot connected to said lever and permitting translation of said orbital movement to the feed-dog whereby to impart feeding movements to the material, means to adjust a part of said universal pivot longitudinally of said lever whereby to vary the length of said feeding movements, and means to fix the relative position of said feed-dog during adjustment of said part.

9. In a sewing machine, a feed-dog, a lever carrying said feed-dog, and means for imparting orbital movement to a part of said lever, a universal pivot connected to said lever and permitting translation of said orbital movement to the feed-dog whereby to impart feeding movements to the material, means to adjust a part of said universal pivot longitudinally of said lever whereby to vary the length of said feeding movements, said universal pivot comprising a collet pivotally attached to said lever and a pivot adjustably and pivotally attached to said collet, and means to fix the relative position of said feed-dog during adjustment of said part.

10. In a sewing machine, a feed-dog having an orbital movement, a feed-dog lever carrying said feed-dog and an eccentric imparting fixed, orbital movement to a part of said lever, aframe carrying the foregoing mechanism, a universal pivot connecting said lever to said frame, said pivot comprising two axes of. oscillation at right angles to each other, means whereby one of said axes may be adjusted longitudinally of said lever, and means to lock said lever to said eccentric during such adjustment.

HOWLAND F. BRIGGS. 

